1. Field of the Invention
This invention relates to a hydraulic oil safety and power system for controlling the supply of steam to a turbine by means of a connecting valve. More particularly, the invention relates to a hydraulic connecting valve system which can be inspected for operational reliability without interrupting the supply of steam to the turbine.
2. Discussion of Background
A connecting valve is known having at least one valve location which is actuated by means of a piston/cylinder arrangement. The piston/cylinder arrangement has a drive volume bounded on one side by the piston. The piston is subjected to a pressure which builds up in the drive volume while forces acting against this build-up of pressure also act on the piston. These forces can again be hydraulically applied pressure forces or also, for example, spring forces.
Such a connecting valve can be actuated and inspected for freedom of movement during a functional inspection but every such actuation has undesirable direct effects on the pressure fluid flow controlled by the valve. Oil is often used as the pressure fluid.
Also known are hydraulic oil safety and power systems in the field of steam supply to a turbine. Such systems act, via a pipework system, on valves and their drives, for example quick-action tripping drives and setting drives, and influence the supply of steam. In such systems, connecting valves are used which, in normal operation, release the supply of the pressure fluid, often oil, into the pipework system.
Such hydraulic oil safety and power systems are often in operation for fairly long periods of time so that the associated connecting valves are not accessible for functional inspections. It is therefore necessary to switch off the complete installation at certain time intervals for inspection purposes; this limits the availability.